WO2015093530A1

WO2015093530A1 - Coated tool

Info

Publication number: WO2015093530A1
Application number: PCT/JP2014/083412
Authority: WO
Inventors: 芳和児玉; 栄仁谷渕; 晃李
Original assignee: 京セラ株式会社
Priority date: 2013-12-17
Filing date: 2014-12-17
Publication date: 2015-06-25
Also published as: US20160326641A1; CN105828991B; KR101822514B1; JP5890594B2; US10174421B2; JPWO2015093530A1; EP3085478B1; EP3085478A4; KR20160088351A; EP3085478A1; CN105828991A

Abstract

Provided is a coated tool with improved wear resistance of an aluminium oxide layer. The coated tool such as a cutting tool (1) is provided with a base material (5) and a coating layer (6) provided to the surface of the base material (5), and having a cutting blade (4) and a relief (3) on the coating layer. The coating layer (6) contains a part in which at least a titanium carbonitride layer (8) and an aluminium oxide layer (10) having a alpha-type crystal structure are laminated in sequence, and with regard to the texture coefficient (Tc) (hkl) which is calculated on the basis of the peak of the aluminium oxide layer (10) analyzed by X-ray diffraction analysis, the texture coefficient (Tc1)(0114) measured from the surface side of the aluminium oxide layer (10) on the relief (3) side is at least 1.0.

Description

Coated tool

The present invention relates to a coated tool having a coating layer on the surface of a substrate.

Conventionally, coating of cutting tools or the like in which one or more titanium carbide layers, titanium nitride layers, titanium carbonitride layers, aluminum oxide layers, titanium aluminum nitride layers, etc. are formed on the surface of a substrate such as cemented carbide, cermet, ceramics, etc. Tools are known.

Such cutting tools are increasingly used in heavy interrupted cutting where a large impact is applied to the cutting edge in accordance with the recent improvement in cutting efficiency. Under such severe cutting conditions, a large amount of coating is required. In order to suppress chipping due to impact and peeling of the coating layer, improvements in fracture resistance and wear resistance are required.

As a technique for improving the fracture resistance in the above cutting tool, Patent Document 1 optimizes the particle size and thickness of the aluminum oxide layer and sets the (012) plane organization coefficient (Texture Coefficient: 1). .3 or more, a technique capable of forming a dense aluminum oxide layer having high fracture resistance is disclosed. Further, in Patent Document 2, by making the organization coefficient in the (012) plane of the aluminum oxide layer 2.5 or more, the residual stress in the aluminum oxide layer is easily released, so that the fracture resistance of the aluminum oxide layer is improved. A technique capable of improving the above is disclosed.

Furthermore, in Patent Document 3, as a technique for improving the wear resistance in the cutting tool, an aluminum oxide layer located immediately above the intermediate layer is formed by laminating two or more unit layers exhibiting different X-ray diffraction patterns. The technique which can improve the intensity | strength and toughness of a film by forming in this way is disclosed.

In Patent Document 4, the (006) plane orientation coefficient of the aluminum oxide layer is increased to 1.8 or more, and the peak intensity ratio I (104) / I (110) between the (104) plane and the (110) plane is A cutting tool controlled to a predetermined range is disclosed.

Further, in Patent Document 5, the peak intensity ratio I (104) / I (012) between the (104) plane and the (012) plane of the aluminum oxide layer is set to be higher than that of the first plane below the aluminum oxide layer. A cutting tool that is larger in surface is disclosed.

Japanese Patent No. 6-316758 Japanese Patent Laid-Open No. 2003-025114 Japanese Patent Laid-Open No. 10-204639 JP 2013-132717 A JP 2009-202264 A

In the coated tools described in Patent Documents 1 to 5, the coating layer has insufficient wear resistance and fracture resistance. In particular, minute chipping occurs in the aluminum oxide layer, and this triggers the wear to easily progress, and further improvement of the aluminum oxide layer has been demanded.

The coated tool of this embodiment includes a base and a coating layer provided on the surface of the base.
Having a cutting edge and a flank on the coating layer;
The coating layer includes at least a portion in which a titanium carbonitride layer and an aluminum oxide layer having an α-type crystal structure are sequentially laminated,
Based on the peak of the aluminum oxide layer analyzed by X-ray diffraction analysis, when the value represented by the following formula is the orientation coefficient Tc (hkl),
The orientation coefficient Tc1 (0 1 14) measured from the surface side of the aluminum oxide layer on the flank side is 1.0 or more.
Orientation coefficient Tc (hkl) = {I (hkl) / I ₀ (hkl)} / [(1/8) × Σ {I (HKL) / I ₀ (HKL)}]
Here, (HKL) is the crystal plane of (012), (104), (110), (113), (024), (116), (124), (0 1 14),
I (HKL) and I (hkl) are the peak intensities I ₀ (HKL) and I ₀ (hkl) of the peaks attributed to the respective crystal planes detected in the X-ray diffraction analysis of the aluminum oxide layer are JCPDS cards No. Standard diffraction intensities of crystal planes described in 43-1484

According to the present embodiment, the peak orientation coefficient Tc1 (0 1 14) measured from the surface side of the aluminum oxide layer on the flank face is as high as 1.0 or more, so that chipping of the aluminum oxide layer is suppressed and resistance to resistance is increased. Abrasion is improved and the coated tool can be used for a long time.

It is a schematic perspective view of the cutting tool which is one Example of the covering tool which concerns on this embodiment. It is a schematic sectional drawing of the cutting tool of FIG.

A cutting tool (hereinafter simply abbreviated as a tool) 1 showing one embodiment of the coated tool of the present embodiment, as shown in FIG. 1, one main surface of the tool 1 is a rake surface 2, and a side surface is a clearance surface 3. The intersecting ridge portion formed by the rake face 2 and the flank face 3 forms a cutting edge 4.

Further, as shown in FIG. 2, the tool 1 includes a base 5 and a coating layer 6 provided on the surface of the base 5. The covering layer 6 is formed by laminating a lower layer 7, a titanium carbonitride layer 8, an intermediate layer 9, an aluminum oxide layer 10, and a surface layer 11 in this order from the substrate 5 side. The aluminum oxide layer 10 has an α-type crystal structure.

In the present embodiment, the value represented by the following formula is defined as the orientation coefficient Tc (hkl) at the peak of the aluminum oxide layer 10 by X-ray diffraction analysis.
Orientation coefficient Tc (hkl) = {I (hkl) / I ₀ (hkl)} / [(1/8) × Σ {I (HKL) / I ₀ (HKL)}]
Here, (HKL) is the crystal plane I (HKL) and I of (012), (104), (110), (113), (024), (116), (124), (0 1 14). (Hkl) is the peak intensity I ₀ (HKL) and I ₀ (hkl) of the peak attributed to each crystal plane detected in the X-ray diffraction analysis of the aluminum oxide layer 10 according to JCPDS card no. 43-1484, the standard diffraction intensity of each crystal plane, and the orientation coefficient Tc1 of the surface side peak measured from the surface side of the aluminum oxide layer 10 on the flank 3 side, and the aluminum oxide layer 10 on the flank 3 side. The orientation coefficient at the substrate-side peak detected by measurement in a state where only a substrate-side portion of the aluminum oxide layer 10 is left is Tc2, and from the surface side of the aluminum oxide layer 10 on the rake face 2 side. It is defined as the orientation coefficient Tc3 of the surface side peak to be measured.

According to this embodiment, the orientation coefficient Tc1 (0 1 14) is 1.0 or more. Thereby, the wear resistance of the aluminum oxide layer 10 is improved. As a result, the tool 1 can be used for a long time. Here, when the orientation coefficient Tc1 (0 1 14) increases, that is, the ratio of the peak intensity I (0 1 14) of the (0 1 14) plane increases, the film formation direction (surface) from the surface side of the aluminum oxide layer 10 increases. It is considered that the aluminum oxide crystal constituting the aluminum oxide layer 10 is easily deformed against an impact applied in a direction perpendicular to the direction, and resistance to breakage is increased. Therefore, on the surface side of the aluminum oxide layer 10, by increasing the orientation coefficient Tc1 (0 アルミニウム 1 14), the minute chipping generated on the surface of the aluminum oxide layer 10 is suppressed, and the wear caused by the minute chipping progresses. It seems to be able to suppress this. A particularly desirable range of Tc1 (0 1 14) is 1.3 to 10, a particularly desirable range is 1.5 to 5, and a further desirable range is 2.0 to 3.5.

Here, according to this embodiment, when Tc1 (0 1 14) and Tc2 (0 1 14) are compared, Tc1 (0 1 14) is larger than Tc2 (0 1 14). That is, Tc2 (0 1 14) is smaller than Tc1 (0 1 14). When the orientation coefficient Tc2 (0 1 14) increases, the coefficient of thermal expansion in the direction parallel to the surface of the aluminum oxide layer 10 and the surface of the intermediate layer 9 and the titanium carbonitride layer 8 below the aluminum oxide layer 10 are parallel. The difference from the coefficient of thermal expansion in the direction increases, and the aluminum oxide layer 10 tends to be peeled off from the intermediate layer 9 and the titanium carbonitride layer 8.

Therefore, peeling of the aluminum oxide layer 10 can be suppressed by reducing Tc2 (0 1 14) of the aluminum oxide layer 10. A desirable range of Tc2 (0 1 14) is 0.3 to 1.5.

Further, a method for measuring Tc2 (0 1 14) and Tc1 (0 1 14) of the aluminum oxide layer 10 will be described. The X-ray diffraction analysis of the aluminum oxide layer 10 is measured using an X-ray diffraction analysis apparatus using a general CuKα ray. In obtaining the peak intensity of each crystal plane of the aluminum oxide layer 10 from the X-ray diffraction chart, the JCPDS card No. The diffraction angle of each crystal face described in 43-1484 is confirmed, the crystal face of the detected peak is identified, and the peak intensity is measured.

Here, the peak detected by X-ray diffraction analysis is identified using a JCPDS card, but the peak position may be shifted due to residual stress or the like present in the coating layer 6. Therefore, in order to confirm whether or not the detected peak is the peak of the aluminum oxide layer 10, an X-ray diffraction analysis is performed with the aluminum oxide layer 10 polished, and the peaks detected before and after polishing are compared. To do. From this difference, it can be confirmed that it is the peak of the aluminum oxide layer 10.

To measure Tc1 (hkl), the surface side peak measured from the surface side of the aluminum oxide layer 10 on the flank 3 side is measured. Specifically, the peak intensity of the aluminum oxide layer 10 is measured from the surface side of the aluminum oxide layer 10 to the base 5 side of the aluminum oxide layer 10. More specifically, X-ray diffraction analysis is performed on the coating layer 6 in a state where the surface layer 11 is removed by polishing or in a state where the surface layer 11 is not polished. The peak intensity of each peak obtained is measured to calculate the orientation coefficient Tc1 (hkl). When the surface layer 11 is polished and removed, a thickness of 20% or less of the thickness of the aluminum oxide layer 10 may be removed. Moreover, even if it is a case where X-ray-diffraction analysis is performed in the state which is not grind | polished with respect to the surface layer 11, it is sufficient if eight peaks of aluminum oxide can be measured. Although the surface side peak is detected including the orientation state of the aluminum oxide layer 10 on the substrate 5 side, the structure state of the aluminum oxide layer 10 near the measurement surface of the X-ray diffraction analysis greatly affects the peak. Therefore, the influence of the orientation state on the substrate 5 side on the surface side peak is small. Tc3 (hkl) is similarly measured based on the surface side peak of the aluminum oxide layer 10 on the rake face 2 side.

In order to measure Tc2 (hkl), a part of the aluminum oxide layer 10 on the flank 3 side is polished, and the peak intensity is measured in a state where only the substrate side portion of the aluminum oxide layer 10 is left. Specifically, first, the aluminum oxide layer 10 of the coating layer 6 is polished to a thickness of 10 to 40% with respect to the thickness of the aluminum oxide layer 10 before polishing. Polishing is performed by brush processing using diamond abrasive grains, processing by an elastic grindstone, or blast processing. Thereafter, the polished portion of the aluminum oxide layer 10 is subjected to X-ray diffraction analysis under the same conditions as those in the surface side portion of the aluminum oxide layer 10, the peak of the aluminum oxide layer 10 is measured, and the orientation coefficient Tc2 ( hkl) is calculated.

Note that the orientation coefficient Tc is an index representing the degree of orientation of each crystal plane because it is determined by the ratio to the non-oriented standard data defined by the JCPDS card. Further, “(hkl)” of Tc (hkl) indicates a crystal plane for calculating the orientation coefficient.

Further, according to the present embodiment, I (104) and I (116) are the first and second strongest in the surface side peak measured from the surface side of the aluminum oxide layer 10 on the flank 3 side. . As a result, flank wear due to minute chipping tends to be suppressed on the flank 3 side. I (0 1 14) is the peak intensity within the eighth, and particularly preferably the third to sixth peak intensity.

Furthermore, according to this embodiment, Tc1 (104) at the surface side peak of the aluminum oxide layer on the flank 3 side is larger than Tc3 (104) at the substrate side peak of the aluminum oxide layer on the flank 3 side. As a result, the flank wear on the flank 3 can be suppressed, and there is an effect of improving the fracture resistance of the cutting tool 1.

As a result of the test, if Tc1 (104) is larger than Tc3 (104), the chipping resistance of the aluminum oxide layer 10 is not sufficiently improved, and Tc1 (0 1 14) is 1.0 or more. It was found that the crater wear resistance of the aluminum oxide layer 10 is greatly improved.

In the present embodiment, the orientation coefficient Tc3 (104) is smaller than Tc1 (104). Thereby, crater wear on the rake face 2 can be suppressed, and chipping resistance on the flank face 3 can be suppressed.

The titanium carbonitride layer 8 is a laminate in which a so-called MT (Moderate Temperature) -titanium carbonitride layer 8a and HT-titanium carbonitride layer 8b are present in this order from the substrate side. The MT-titanium carbonitride layer 8a is made of columnar crystals containing acetonitrile (CH ₃ CN) gas as a raw material and formed at a relatively low film formation temperature of 780 to 900 ° C. The HT (High Temperature) -titanium carbonitride layer 8b is made of granular crystals formed at a high film formation temperature of 950 to 1100.degree. According to this embodiment, the surface of the HT-titanium carbonitride layer 8b is formed with triangular projections in a cross-sectional view that tapers toward the aluminum oxide layer 10, thereby increasing the adhesion of the aluminum oxide layer 10. Further, peeling and chipping of the coating layer 6 can be suppressed.

Further, according to this embodiment, the intermediate layer 9 is provided on the surface of the HT-titanium carbonitride layer 8b. The intermediate layer 9 contains titanium and oxygen, and is made of, for example, TiAlCNO, TiCNO, or the like. FIG. 2 is made up of a lower intermediate layer 9a and an upper intermediate layer 9b on which these are laminated. As a result, the aluminum oxide particles constituting the aluminum oxide layer 10 have an α-type crystal structure. The aluminum oxide layer 10 having an α-type crystal structure has high hardness, and can improve the wear resistance of the coating layer 6. Since the intermediate layer 9 has a laminated structure of the lower intermediate layer 9a made of TiAlCNO and the upper intermediate layer 9b made of TiCNO, there is an effect of improving the fracture resistance of the cutting tool 1. The titanium carbonitride layer 8 is provided with a thickness of 6.0 to 13.0 μm, and the intermediate layer 9 is provided with a thickness of 0.05 to 0.5 μm.

Furthermore, the lower layer 7 and the surface layer 11 are made of titanium nitride. In other embodiments, at least one of the lower layer 7 and the surface layer 11 may not be provided. The lower layer 7 is provided with a thickness of 0.1 to 1.0 μm, and the surface layer 11 is provided with a thickness of 0.1 to 3.0 μm.

The thickness of each layer and the properties of the crystals constituting each layer should be measured by observing an electron micrograph (scanning electron microscope (SEM) photograph or transmission electron microscope (TEM) photograph) in the cross section of the tool 1. Is possible. In the present embodiment, the crystal form of the crystals constituting each layer of the coating layer 6 is columnar. The average ratio of the average crystal width to the length in the thickness direction of the coating layer 6 of each crystal is 0 on average. .3 or less states. On the other hand, when the ratio of the average crystal width to the length in the thickness direction of the coating layer of each crystal exceeds 0.3 on average, the crystal form is defined as granular.

On the other hand, the base 5 of the tool 1 is a hard material composed of tungsten carbide (WC) and, if desired, at least one selected from the group consisting of carbides, nitrides, and carbonitrides of

Group

4, 5, and 6 metals of the periodic table. Cemented carbide, Ti-based cermet, or Si ₃ N ₄ , Al ₂ O ₃ , diamond, cubic nitridation in which phases are bonded with a binder phase composed of an iron group metal such as cobalt (Co) or nickel (Ni) Ceramics such as boron (cBN) can be used. Especially, when using as a cutting tool like the tool 1, the base | substrate 5 may consist of a cemented carbide or a cermet from the point of a fracture resistance and abrasion resistance. Further, depending on the application, the base 5 may be made of a metal such as carbon steel, high-speed steel, or alloy steel.

Furthermore, the said cutting tool applies the cutting edge 4 formed in the cross | intersection part of the rake face 2 and the flank 3 to a to-be-cut object, and can cut it, and can exhibit the outstanding effect mentioned above. . In addition to the cutting tool, the coated tool of the present embodiment can be applied to various uses such as an excavation tool and a blade, and in this case also has excellent mechanical reliability.

Next, the manufacturing method of the coated tool according to the present invention will be described with reference to an example of the manufacturing method of the tool 1.

First, metal powder, carbon powder, etc. are appropriately added to and mixed with inorganic powder such as metal carbide, nitride, carbonitride, oxide, etc. that can form a hard alloy to be the base 5 by firing, press molding, casting After forming into a predetermined tool shape by a known forming method such as forming, extrusion forming, cold isostatic pressing, etc., the substrate 5 made of the hard alloy described above is fired in a vacuum or non-oxidizing atmosphere. Make it. Then, the surface of the substrate 5 is subjected to polishing or honing of the cutting edge as desired.

Next, a coating layer is formed on the surface by chemical vapor deposition (CVD).

First, a mixed gas composed of 0.5 to 10% by volume of titanium tetrachloride (TiCl ₄ ) gas, 10 to 60% by volume of nitrogen (N ₂ ) gas, and the balance of hydrogen (H ₂ ) gas is prepared as a reaction gas composition. Then, the film is introduced into the chamber, and the TiN layer as the lower layer 7 is formed at a film forming temperature of 800 to 940 ° C. and 8 to 50 kPa.

Thereafter, the reaction gas composition is 0.5 to 10% by volume of titanium tetrachloride (TiCl ₄ ) gas, 5 to 60% by volume of nitrogen (N ₂ ) gas, and 0.1% of acetonitrile (CH ₃ CN) gas as the reaction gas composition. An MT-titanium carbonitride layer is prepared by adjusting a mixed gas consisting of 1 to 3.0% by volume and the remainder of hydrogen (H ₂ ) gas into the chamber and setting the film forming temperature to 780 to 880 ° C. and 5 to 25 kPa. Is deposited. At this time, by increasing the content ratio of acetonitrile (CH ₃ CN) gas in the later stage of film formation than in the initial stage of film formation, the average crystal width of the titanium carbonitride columnar crystals constituting the titanium carbonitride layer is more on the surface side than on the substrate side. This can be a larger configuration.

Next, an HT-titanium carbonitride layer constituting the upper portion of the titanium carbonitride layer 8 is formed. According to this embodiment, the specific film forming conditions of the HT-titanium carbonitride layer are as follows: titanium tetrachloride (TiCl ₄ ) gas is 1 to 4% by volume, nitrogen (N ₂ ) gas is 5 to 20% by volume, A mixed gas composed of 0.1 to 10% by volume of methane (CH ₄ ) gas and the remaining hydrogen (H ₂ ) gas is prepared and introduced into the chamber, and the film forming temperature is set to 900 to 1050 ° C. and 5 to 40 kPa. Form a film.

Further, the intermediate layer 9 is produced. The specific film forming conditions for this embodiment are as follows. As a first step, titanium tetrachloride (TiCl ₄ ) gas is 3 to 30% by volume, methane (CH ₄ ) gas is 3 to 15% by volume, nitrogen (N ₂ ) 5-10% by volume of gas, 0.5-1% by volume of carbon monoxide (CO) gas, 0.5-3% by volume of aluminum trichloride (AlCl ₃ ) gas, the remainder being hydrogen (H ₂ ) gas The mixed gas consisting of These mixed gases are adjusted and introduced into the chamber to form a film at a film forming temperature of 900 to 1050 ° C. and 5 to 40 kPa. By this step, an intermediate layer 9 having irregularities on the surface of the titanium carbonitride layer 8 is formed.

Subsequently, as the second stage of the intermediate layer 9, titanium tetrachloride (TiCl ₄ ) gas is 3 to 15% by volume, methane (CH ₄ ) gas is 3 to 10% by volume, and nitrogen (N ₂ ) gas is 10 to 25%. A mixed gas comprising volume%, carbon monoxide (CO) gas in an amount of 1 to 5 volume%, and the remainder consisting of hydrogen (H ₂ ) gas is prepared. These mixed gases are adjusted and introduced into the chamber to form a film at a film forming temperature of 900 to 1050 ° C. and 5 to 40 kPa. In this step, the nitrogen (N ₂ ) gas may be changed to argon (Ar) gas. By this step, the unevenness on the surface of the intermediate layer 9 becomes fine, and the growth state of the aluminum oxide crystal in the aluminum oxide layer 10 to be formed next can be adjusted.

Then, an aluminum oxide layer 10 is formed. First, nuclei of aluminum oxide crystals are formed. 5 to 10% by volume of aluminum trichloride (AlCl ₃ ) gas, 0.1 to 1.0% by volume of hydrogen chloride (HCl) gas, 0.1 to 5.0% by volume of carbon dioxide (CO ₂ ) gas, A mixed gas consisting of hydrogen (H ₂ ) gas is used, and the temperature is set to 950 to 1100 ° C. and 5 to 10 kPa. By the first stage film formation, the growth state of the aluminum oxide crystal to be formed is changed, and the Tc (0 1 14) of the aluminum oxide layer 10 is controlled.

Next, 0.5 to 5.0% by volume of aluminum trichloride (AlCl ₃ ) gas, 1.5 to 5.0% by volume of hydrogen chloride (HCl) gas, and 0.5% of carbon dioxide (CO ₂ ) gas. -5.0% by volume, hydrogen sulfide (H ₂ S) gas is 0 to 1.0% by volume, and the remainder is hydrogen (H ₂ ) gas mixed gas, and is changed to 950 to 1100 ° C. and 5 to 20 kPa. Form a film. By this second stage film formation process, the growth state of the aluminum oxide crystal formed on the substrate side of the aluminum oxide layer 10 is adjusted to control the substrate side Tc (0 1 14).

Subsequently, 5 to 15% by volume of aluminum trichloride (AlCl ₃ ) gas, 0.5 to 2.5% by volume of hydrogen chloride (HCl) gas, and 0.5 to 5.0 of carbon dioxide (CO ₂ ) gas. Using a mixed gas consisting of volume%, hydrogen sulfide (H ₂ S) gas of 0.0 to 1.0 volume% and the remainder of hydrogen (H ₂ ) gas, the temperature is changed to 950 to 1100 ° C. and 5 to 20 kPa for oxidation. An aluminum layer 10 is formed. By this third stage film formation process, the growth state of the aluminum oxide crystal formed on the surface side of the aluminum oxide layer 10 is adjusted to control the surface side Tc (0 1 14).

Then, a surface layer (TiN layer) 11 is formed as desired. Specific film forming conditions are as follows: titanium tetrachloride (TiCl ₄ ) gas is 0.1 to 10% by volume, nitrogen (N ₂ ) gas is 10 to 60% by volume, and the remainder is hydrogen (H ₂ ) gas. A mixed gas consisting of the above is adjusted and introduced into the chamber, and the film is formed at a film forming temperature of 960 to 1100 ° C. and 10 to 85 kPa.

Thereafter, if desired, at least the cutting edge portion of the surface of the formed coating layer 6 is polished. By this polishing process, the cutting edge portion is processed smoothly, the welding of the work material is suppressed, and the tool is further excellent in fracture resistance.

First, 6% by mass of metallic cobalt powder having an average particle size of 1.2 μm, 0.5% by mass of titanium carbide powder having an average particle size of 2.0 μm, 5% by mass of niobium carbide powder having an average particle size of 2.0 μm, and the balance Were added and mixed at a ratio of tungsten carbide powder having an average particle size of 1.5 μm, and formed into a tool shape (CNMG120408) by press molding. Then, the binder removal process was performed, and it fired for 1 hour in the vacuum of 1500 degreeC and 0.01 Pa, and produced the base | substrate which consists of a cemented carbide. Thereafter, the fabricated substrate was subjected to brushing, and R honing was applied to the portion to be the cutting edge.

Next, a coating layer was formed on the cemented carbide substrate by the chemical vapor deposition (CVD) method under the film formation conditions shown in Table 1 to produce a cutting tool. In Tables 1 and 2, each compound is represented by a chemical symbol.

For the sample, first, X-ray diffraction analysis using CuKα rays was performed on the rake face without polishing the coating layer, and each of the (0 1 14) plane, (104) plane, and (116) plane of the JCPDS card was measured. The orientation coefficient Tc3 (hkl) of the crystal plane was calculated. Next, on the flat surface of the flank, the surface side peak measured from the surface side of the aluminum oxide layer by performing X-ray diffraction analysis using CuKα rays without polishing the coating layer (in the table, the surface side or the surface) (Identified as side peak) and the peak intensity of each peak was measured. Further, regarding the surface side peak, the highest intensity peak and the second highest intensity peak were confirmed, and the (0 結晶 1 14) plane, (104) plane, and (116) plane of each crystal plane of the JCPDS card were also confirmed. An orientation coefficient Tc1 (hkl) was calculated. In addition, the flank is polished until it becomes 10 to 40% of the thickness of the aluminum oxide layer. Similarly, by X-ray diffraction analysis, a part of the aluminum oxide layer is polished to leave only the substrate side portion. The substrate-side peak (denoted as the substrate side in the table) measured in step 1 and the peak intensity of each peak were measured. Using the peak intensity of each obtained peak, the orientation coefficient Tc2 (hkl) of each crystal plane of the (0） 1 14) plane, (104) plane, and (116) plane was calculated. In addition, the said X-ray-diffraction measurement measured about three arbitrary samples, and evaluated it with the average value. Moreover, the fracture surface of the said tool was observed with the scanning electron microscope (SEM), and the thickness of each layer was measured. The results are shown in Tables 2-4.

Next, using the obtained cutting tool, a continuous cutting test and an intermittent cutting test were performed under the following conditions to evaluate wear resistance and fracture resistance. The results are shown in Table 4.
(Continuous cutting conditions)
Work Material: Chromium Molybdenum Steel (SCM435)
Tool shape: CNMG120408
Cutting speed: 300 m / min Feeding speed: 0.3 mm / rev
Cutting depth: 1.5mm
Cutting time: 25 minutes Others: Use of water-soluble cutting fluid Evaluation item: Observe the honing part of the edge with a scanning electron microscope, and in the part that is actually worn, the flank wear width on the flank and the crater wear on the rake face Measure width.
(Intermittent cutting conditions)
Work Material: Chromium Molybdenum Steel Four Grooved Steel (SCM440)
Tool shape: CNMG120408
Cutting speed: 300 m / min Feeding speed: 0.3 mm / rev
Cutting depth: 1.5mm
Others: Use of water-soluble cutting fluid Evaluation item: Measures the number of impacts leading to defects.

According to the results of Tables 1 to 4, the sample No. 1 in which the Tc1 (0 1 14) of the surface side peak of the aluminum oxide layer on the flank face is less than 1.0. In all of Nos. 8 to 10, wear progressed quickly and the aluminum oxide layer was easily peeled off by impact.

On the other hand, Sample No. Tc1 (0１1 14) is 1.0 or more. In Nos. 1 to 7, minute chipping of the aluminum oxide layer was suppressed, and almost no peeling occurred. In particular, in the surface side peak of the aluminum oxide layer, the sample No. 1 in which the (104) plane and (116) plane consist of the first and second highest peaks. For samples 1 to 4 and 6, sample no. Compared to 5 and 7, the crater wear width was smaller and the wear resistance was particularly excellent. In addition, the sample No. 1 in which the substrate-side orientation coefficient Tc2 (0 1 14) is smaller than the surface-side orientation coefficient Tc1 (0 1 14). Nos. 1 to 6 had particularly small crater wear. Furthermore, the sample No. 2 in which the orientation coefficient Tc3 (104) of the surface side peak on the rake face is smaller than the orientation coefficient Tc1 (104) of the surface side peak on the flank face. In Nos. 1 to 6, the number of impacts that led to defects was particularly large.

DESCRIPTION OF SYMBOLS 1 ... Cutting tool 2 ... Rake face 3 ... Flank 4 ... Cutting blade 5 ... Base body 6 ... Cover layer 7 ... Lower layer 8 ... Titanium carbonitride layer 8a ..MT-titanium carbonitride layer 8b ... HT-titanium carbonitride layer 9 ... intermediate layer 9a ... lower intermediate layer 9b ... upper intermediate layer 10 ... aluminum oxide layer 11 ... surface layer

Claims

A substrate and a coating layer provided on the surface of the substrate;
Having a cutting edge and a flank on the coating layer;
The coating layer includes at least a portion in which a titanium carbonitride layer and an aluminum oxide layer having an α-type crystal structure are sequentially laminated,
Based on the peak of the aluminum oxide layer analyzed by X-ray diffraction analysis, the value represented by the following formula is measured from the surface side of the aluminum oxide layer on the flank side when the orientation coefficient is Tc (hkl). A coated tool having an orientation coefficient Tc1 (0 1 14) of 1.0 or more.
Orientation coefficient Tc (hkl) = {I (hkl) / I 0 (hkl)} / [(1/8) × Σ {I (HKL) / I 0 (HKL)}]
Here, (HKL) is the crystal plane of (012), (104), (110), (113), (024), (116), (124), (0 1 14),
I (HKL) and I (hkl) are the peak intensities I 0 (HKL) and I 0 (hkl) of the peaks attributed to the respective crystal planes detected in the X-ray diffraction analysis of the aluminum oxide layer are JCPDS cards No. Standard diffraction intensities of crystal planes described in 43-1484
An orientation coefficient Tc2 (0 1 14) detected by measurement in a state where a part of the aluminum oxide layer on the flank side is polished and only the base portion of the aluminum oxide layer is left is Tc1 ( The coated tool according to claim 1, which is smaller than 0 1 14).
The coated tool according to claim 1 or 2, wherein I (104) and I (116) are the first and second strongest in the surface side peak measured from the surface side of the aluminum oxide layer on the flank side.
An orientation coefficient Tc3 (104) measured from the surface side of the aluminum oxide layer on the rake face side is further measured from the surface side of the aluminum oxide layer on the flank face side. The coated tool according to any one of claims 1 to 3, wherein the coated tool is smaller than an orientation coefficient Tc1 (104).